Meningio-angiomatosis — case report and subject review

A 6-year-old girl presented after a prolonged grand mal seizure. She had suffered from recurrent focal seizures affecting her right side since 1 year of age and also suffered from a mild right-sided hemiplegia. There were no clinical or radiological stigmata of NF. An electro-encephalogram (EEG) demonstrated abnormal electrical activity over both temporoparietal regions. An unenhanced computed tomography (CT) scan of the brain showed multiple areas of hyperintensity in the left parietal lobe extending in a linear radial fashion along a number of gyni and sulci over the surface of the brain (Fig. 1a). Moderate contrast enhancement was seen adjacent to some of these hyperintensities (Fig. 1b). The hyperintense areas appeared denser than blood. As there was no suspicion of any acute subarachnoid haemorrhage this was assumed to be calcification. On unenhanced T1-weighted magnetic resonance (MR) images no direct evidence of any meningeal thickening could be seen, although slight thickening and a mild increase in signal intensity was seen within the cortex over the convexity of the parietal lobe (Fig. 2a). No abnormal signal intensity was noted in this area on T2-weighted or proton-density images, although some prominent vessels were seen over the brain surface (Fig. 2b). Bright signal was, howCASE REPORT


Introduction
Meningio-angiomatosis (MA) is a rare congenital hamartomatous malformation of the leptomeninges often also involving the adjacent cerebral cortex.Some cases are associated with neurofibromatosis (NF) whereas others develop in isolation.

Case report
A 6-year-old girl presented after a prolonged grand mal seizure.She had suffered from recurrent focal seizures affecting her right side since 1 year of age and also suffered from a mild right-sided hemiplegia.There were no clinical or radiological stigmata of NF.An electro-encephalogram (EEG) demonstrated abnormal electrical activity over both temporoparietal regions.
An unenhanced computed tomography (CT) scan of the brain showed multiple areas of hyperintensity in the left parietal lobe extending in a linear radial fashion along a number of gyni and sulci over the surface of the brain (Fig. 1a).Moderate con-trast enhancement was seen adjacent to some of these hyperintensities (Fig. 1b).The hyperintense areas appeared denser than blood.As there was no suspicion of any acute subarachnoid haemorrhage this was assumed to be calcification.
On unenhanced T1-weighted magnetic resonance (MR) images no direct evidence of any meningeal thickening could be seen, although slight thickening and a mild increase in signal intensity was seen within the cortex over the convexity of the parietal lobe (Fig. 2a).No abnormal signal intensity was noted in this area on T2-weighted or proton-density images, although some prominent vessels were seen over the brain surface (Fig. 2b   ever, noted on the post-gadolinium FLAIR (Fig. 2c) and post-gadolinium T1-weighted images (Figs 2d -f).
Digital subtraction arteriography was then performed.Selective left external carotid arteriograms showed no abnormal dural supply, whereas selective left internal carotid arteriograms showed enlargement of the posterior parietal branch of the left middle cerebral artery with some smaller slightly dysplastic looking branches seen in the same area as the abnormalities shown on the scan (Figs 3a -d).
The diagnosis of meningiomatosis was made on the basis of the clinical and radiological findings, but the child has since been lost to follow-up with the result that no histological confirmation could be obtained.

Discussion
MA is a rare benign hamartomatous lesion of the cerebral cortex and adjacent leptomeninges, first described by Bassoe and Nuzum 1 in 1915 in a patient with NF.The term 'meningio-angiomatosis' was first used in 1937 by Worcester-Drought et al., 2 who also first suggested that MA may represent a forme fruste of NF.Many cases have been reported in NF patients, but not all are associated with NF. [3][4][5] In sporadic cases the male/female ratio is more equal and the mean patient age tends to be somewhat younger, children and young adults being affected.Patients typically present clinically with headaches and seizures but some cases are also found incidentally at autopsy 6,7 or during cranial imaging. 8In most cases the MA affects the cerebral cortex, usually in the frontal or temporal regions.Some cases may show    involvement of the third ventricle, thalamus or brainstem. 6,9he characteristic pathological findings include leptomeningeal meningovascular fibroblastic proliferation and a variable degree of leptomeningeal calcification. 3,10There is angiomatous proliferation within the meninges, sometimes with associated arteriovenous shunting.The fibroblastic and angiomatous proliferation can extend in a linear fashion along the Virchow-Robin perivascular spaces, thereby appearing to 'penetrate' the cortical grey matter. 3The degree of calcification can vary from numerous psammona bodies histoto dense calcification and even ossification. 8Changes may also be seen in the adjacent brain cortex (mengiocephalo-angioneuromatosis).The cortical changes include the presence of neurofibrillary tangles, thought to represent degenerative changes in entrapped neurons. 6n unenhanced CT scans the calcifications may be seen as either linear or granular in nature, 3 whereas noncalcified areas or lesions may range from isodense to moderately hypodense with the low-density appearance probably representing a loosely packed cellular matrix consisting of prominent perivascular spaces and scattered meningeal spindle (fibrous) cells. 7The degree of contrast enhancement is variable.On MR scans the lesions tend to be iso-to hypointense to grey matter on T1-weighted images.Non-calcified areas or lesions are typically hyperintense on T2weighted images with areas of dense calcification producing marked T2 shortening and thus appearing as hypo-intense areas often within the center of the lesion. 3,8,10Again contrast enhancement is variable.Angiographic findings also vary from normal through the presence of an avascular 'mass' to the finding of abnormal vessels. 4,8,10he differential diagnosis of MA includes the Sturge-Weber syndrome, meningioma, granulomatous meningitis (sarcoid or tuberculosis) and calcified infiltrating glioma.][6]

CASE REPORT
Fig 1a.Unenhanced axial CT scan showing linear hyperintense material over the surface of the left parietal lobe with extension into the sulci in keeping with calcified proliferative leptomeningeal tissue.

Fig 2b .
Fig 2b.No significant signal abnormality is noted on either standard T2-weighted or proton-density images (illustrated here).Some prominent surface vessels are seen.

Fig
Fig 1b.Contrast-enhanced CT scan at the same level showing some areas of contrast enhancement within the abnormal tissue.

Fig
Fig 2d.Contrast-enhanced coronal T1-weighted image showing the enhancing thickened leptomeninges over the brain surface.

Fig
Fig 2e.Contrast-enhanced axial T1-weighted image at the same level as Fig 2b showing the densely-enhancing surface tissue and sulcal extension.

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Fig 2f.Contrast-enhanced sagittal T1-weighted image showing the anteroposterior extent of the lesion.Note the radial extension within the sulci and possibly through the perivascular spaces as well.

Fig 3c .
Fig 3c.Same vessel, right anterior oblique view, again showing the relatively prominent parietal branch.